Chemical defense mechanisms and genetic polymorphism.

leading to "less desirable" conditions in the estuary. Studies of the effects of thermal discharges have failed to document any substantial damage from present inputs. Perhaps the most disturbing aspects of Holden's articles are contained not in her "floating statistics," but in the following three sentences: "Although the bay has long been a laboratory for marine scientists, no comprehensive plan has yet been developed to protect its bounty and order its progress.... Is the bay dying and if so what can be done to save it? Decisive action will have to await more detailed understanding of the bay." Holden's implication that scientists should devise a master plan for the management and utilization of this great natural resource is perilous, and her statement that there is presently not sufficient scientific information for any decisive action is erroneous. There are certainly countless unanswered scientific questionsthere always will be. But the general features of many of the important processes in the bay are known and understood, and scientific predictions can be made. In many respects, scientific information has developed at a faster rate than management's ability to utilize it. Decisions of how to manage the Chesapeake Bay, of how to "order its progress," require not only scientific inputs, but social and economic inputs as well. Management problems rarely have unequivocal answers. They are very frequently value judgments, and natural scientists have no peculiar talents for making such decisions. Science cannot solve all of man's problems, environmental or otherwise. It cannot incontestably determine either what uses of the bay are most important, or even what uses are most desirable. Through science we can learn to understand the bay and even, in part, to control it, but science cannot unequivocally and decisively determine the ways in which we shouild control it. Scientists can, however, help to design and implement the actions necessary to the attainment of the desired ends, once those ends have been selected. Decisive action does not "await a more detailed understanding of the bay." It awaits a crisis. And there is little evidence to suggest that such "decisive action" will be predicated on scientific knowledge. The Chesapeake Bay has served her many masters well, and she continues to do so. The bay is healthy, but it requires nonsimplistic management. J. R. SCHUBEL D. W. PRITCHARD Chesapeake Bay Institute, Johns Hopkins University, Baltimizore, Maryland 21218